Circuitry that detects a phase difference between a first, base, clock and a second, derivative, clock derived from the base clock
US5703502A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 1996 |
| Grant date | Dec 30, 1997 |
| Priority date | — |
| Expiry date | May 30, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D13/001
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A phase detection circuit detects a phase relationship between a first clock signal, characterized by transitions of a given polarity (e.g., rising edges) at a first frequency, and a second clock signal, characterized by transitions of the given polarity at a second frequency that is an integer multiple of the first frequency. Transition indication circuitry generates a transition indication signal responsive to transitions, of the given polarity, of the second clock signal. The transition indication signal includes a transition indication (e.g., a pulse) corresponding to each n.sup.th transition, of the given polarity, of the second clock signal and at a phase that is selectable relative to the first clock signal in response to a transition indication control signal. Sampling circuitry (e.g., one or more latches) samples the transition indication signal responsive to each transition, of the given polarity, of the first clock signal to generate a transition indication sample. Coincidence determination circuitry determines, responsive to the transition indication sample signal and to the second clock signal, if the transition indication coincides with a transition, of the given pola…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.